The present invention relates to an apparatus for evacuating personnel from an offshore platform. More particularly, this invention relates to a stowable launching ramp that is gimballed to the downward side of the platform and a survival craft launchable therefrom to get personnel away from the platform in all weather conditions.
Conventional personnel evacuation equipment for offshore platforms has been adapted from ships and generally comprises some form of life boat that can be lowered to the surface of the water using a davit or similar crane mechanism. Many systems currently in use have not changed appreciable in 75 years. Such devices may be suitable for usage in "duck pond" conditions where a fire, or the like, is the reason evacuation is necessary. However, in a severe storm that threatens the stability of the platform and, accordingly, the lives of all personnel manning the platform, to leave the platform in such a craft is not unlike jumping from the frying pan into the fire. Conventional life boats will capsize in a matter of minutes in such a storm. Even self-righting survival vessels are in jeopardy of being smashed to pieces by wave action against the below-deck portions of the platform or subject to being blown off the supports by high winds or snapping of the cables due to excessive loading during lowering to the surface of the ocean. A safer means of evacuating personnel to an acceptable distance from the platform is required.
The present invention provides such a system. A self-righting survival vessel is maintained in a launching ramp by releasable securing means. The launching ramp is stored in a substantially vertical position by engagement of a catch on the exit end of said ramp with latch means on the sub-sea portion of the platform that can be released from the deck of the platform. Once released, the exit end of the launching ramp is moved to its deployed position by flotation means. The launching ramp is mounted on a deck of the platform by a universally gimballed connection which permits the exit end of the ramp to pivot to a downwind position and to accommodate the movement of the waves vis a vis the deck of the platform as well as permitting the pitch, roll and yaw of the deck itself (at least 25.degree. from vertical in any direction).
The lateral pivoting of the ramp is limited at .+-.50.degree. from perpendicular relative to the edge of the platform upon which the evacuation system is mounted so that the survival vessel cannot be discharged too near to the platform thereby jeopardizing the vessel's occupants. Once the launching ramp is deployed, the survival vessel can be manned and the release mechanism disengaged so as to release the vessel. The vessel will be gravity-launched onto the ocean so that the momentum of the craft will carry it away from the platform. Further, prevailing winds will ordinarily carry the vessel away from the platform since the launching ramp is preferably gimballed to the downward side of the platform. There are preferably at least two parallel launching ramps making possible simultaneous multiple craft deployment.
Other features, characteristics and advantages of the present invention will become apparent after a reading of the following detailed description .